Some troops are used to acting in pairs, working in perfect synchronization as one tactical element. This combat binomial tends to be formed by troops of the same quality, although within certain units a senior or veteran operative is in charge of the decision making on the ground, or is tasked with the instruction of the other member who tends to be a rookie operative. In penal units, this works as an imposed order, in which each member of the binomial is responsible for the other. So if one of them disobeys the orders, both of them will be punished.